Steerable, all-wheel drive construction equipment are old and well known to the art. Originally designed to operate with only a loading scoop or a bucket, these machines have, with the provision of specifically designed attachments, evolved into multi-purpose machines capable of many diverse operations. Nowadays, a steerable, all-wheel drive machine may be configured to operate as a trencher, street sweeper, a posthole digger, a forklift, a trencher, or a boom lift, for example. Trenchers are used to dig channels, typically for laying pipes or cable, or for drainage. Depending on the type of digging implement, a trencher may be classified as a chain trencher, a rockwheel trencher, or a plow. A chain trencher excavates the ground with a specialized, closed loop chain that digs into and removes earth, and which is driven around a rounded metal frame or boom, similar to a chainsaw. This type of trencher can be used to excavate in situations where it is difficult, slow, or impractical to be with traditional backhoe type excavators. In operation, the angle of the boom can be adjusted to control the depth of the cut. To excavate a trench, the boom is held at a fixed angle while the machine slowly traverses forward. A rockwheel trencher is a large diameter disc that is provided with teeth about its circumference, and is similar to a circular saw. Rockwheel trenchers can excavate harder ground than a chain trencher, and is particularly useful in situations where the_trench traverses solid stone. On a smaller scale, rockwheel trenchers can also be used to make incisions into pavement for road maintenance and/or to gain access to utilities under roads.
The cable plow is specialized form of plow that is configured to pass through the earth with a minimum of above-surface disruption. The typical cable plow is an elongated blade that has a small cross-sectional area. These types of plows are useful in situations where the ground is comparatively soft. In situations where the ground is sticky or hard, the plow may be vibrated so as to ease its passage as it moves along. The bottom or lower portion of the blade plow can be attached to a cable so that the cable will be pulled along with the blade as it traverses the ground, or laid down in the trench as the plow advances.
As will be understood, such vehicles are best utilized on solid, horizontal surfaces. The present invention provides a solution to these needs and other problems, and offers other advantages over the prior art.